Inclusion Criteria:

1. Provides written informed consent prior to initiation of any study procedures.

2. Able to understand and agrees to comply with planned study procedures and be
available for all study visits.

3. Non-pregnant adults, 18 through 64 years of age, inclusive at time of study product
administration.

4. Participants of childbearing potential* must agree to use or have practiced true
abstinence** or use at least one acceptable primary form of contraception*** *These
criteria apply to females who are in a heterosexual relationship who are of
childbearing potential. Not of childbearing potential include post-menopausal
females (defined as having a history of amenorrhea for at least one year) or a
documented status as being surgically sterile (hysterectomy, bilateral oophorectomy,
or tubal ligation/salpingectomy).

**True abstinence is 100% of the time, no sexual intercourse (penis enters the
vagina). Periodic abstinence [e.g., calendar, ovulation, symptothermal,
post-ovulation methods] and withdrawal are not acceptable methods.

***Acceptable forms of primary contraception include a monogamous relationship with
a vasectomized partner who has been vasectomized for 180 days or more before the
participant's study product administration, intrauterine devices, birth control
pills, and injectable/implantable/insertable/transdermal hormonal birth control
products. Must have used at least one acceptable primary form of contraception for
at least 30 days before study product administration and agree to continue at least
one acceptable primary form of contraception through 60 days after study product
administration.

5. Participants of childbearing potential must have a negative urine pregnancy test at
screening and within 24 hours prior to study product administration.

6. In general self-reported, good health.****

****As determined by medical history and physical examination, including vital
signs, to evaluate acute or ongoing chronic medical diagnoses/conditions that have
been present for at least 90 days, which would affect the assessment of the safety
of participants. Chronic medical diagnoses/conditions should be stable for the last
30 days (i.e., no hospitalizations, ER, or urgent care for the condition). This
includes no change in chronic prescription medication, dose, or frequency due to
deterioration of the chronic medical diagnosis/condition 30 days before the study
product administration. Any prescription change due to a change of health care
provider, insurance company, etc., or done for financial reasons and in the same
class of medication will not be considered a deviation of this inclusion criterion.
Participants may be on chronic or as-needed (prn) medications if, in the opinion of
the participating site PI or appropriate sub-investigator, they pose no additional
risk to participant safety or assessment of reactogenicity and immunogenicity.

7. Receipt of a complete primary authorized or approved COVID-19 vaccine series and at
least one booster***** with last vaccination at least 16 weeks prior to study
product administration.

*****Primary series and/or booster may have been received as part of participation
in a clinical trial (see MOP for further details).

8. Clinical screening laboratory evaluations are within normal reference ranges or
grade 1 with no clinical significance (NCS) per investigator discretion.

9. Must agree to have samples stored for secondary research.

Exclusion Criteria:

1. Positive SARS-CoV-2 PCR at screening.

2. Abnormal vital signs at screening (Grade 1 or higher)*:

*Grade 1 or higher is equivalent to: Systolic blood pressure (SBP) > / =141 mmHg or
< / = 89 mmHg Diastolic blood pressure (DBP) > / =91 mmHg Heart rate (HR) is > /
=101 beats per minute or < / = 54 beats per minute Oral temperature > / =38.0°C
(100.4°F)

3. History of SARS-CoV-2 infection or receipt of any COVID-19 vaccine < 16 weeks prior
to study product administration.

4. Pregnant or breastfeeding.

5. Blood or plasma donation within 4 weeks prior to planned study product
administration.

6. Receipt of antibody or blood-derived products within 90 days prior to planned study
product administration.

7. Any self-reported or documented significant medical or psychiatric diseases** or any
other condition that, in the opinion of the site PI or appropriate sub-investigator,
precludes study participation.

**Significant medical or psychiatric conditions include but are not limited to
significant kidney disease, liver disease, history of hematologic malignancy,
ongoing other malignancy or recent diagnosis of malignancy in the last five years
excluding treated basal cell and squamous cell carcinoma of the skin, and cervical
carcinoma in situ, which are allowed.

8. History of any significant neurological or neurodevelopmental conditions.***

***Including history of Bell's palsy, history of four or more migraine headaches in
the past 12 months that interfered with normal daily activity or any migraine
headache in the past 5 years that required emergency or inpatient medical care,
epilepsy, seizures in the last 5 years, encephalopathy, focal neurologic deficits,
Guillain-Barré syndrome, encephalomyelitis, transverse myelitis, stroke or transient
ischemic attack, multiple sclerosis, Parkinson's disease, amyotrophic lateral
sclerosis, Creutzfeldt-Jakob disease, or Alzheimer's disease.

9. History of significant respiratory disease requiring daily medications currently,
history of asthma in the past 5 years, or any treatment of respiratory disease
exacerbations in the last 5 years.

10. History of cardiovascular disease (e.g., congestive heart failure, cardiomyopathy,
ischemic heart disease), including any history of myocarditis or pericarditis, or
uncontrolled cardiac arrhythmia.

11. Any autoimmune disease, including hypothyroidism, without a defined non-autoimmune
cause.

12. Has an acute illness, as determined by the site PI or appropriate sub-investigator
within 72 hours prior to study product administration.****

****An acute illness that is nearly resolved with only minor residual symptoms
remaining is allowable if, in the opinion of the participating site PI or
appropriate sub-investigator, the residual symptoms will not interfere with the
ability to assess safety parameters as required by the protocol.

13. Has a positive test result for hepatitis B surface antigen, hepatitis C virus RNA
(by reflex testing), or human immunodeficiency virus (HIV) antigen/antibody test at
screening.

14. Has any confirmed or suspected immunosuppressive or immunodeficient state such as
asplenia, recurrent severe infections, or chronic***** immunosuppressant medication
within the past 6 months or is planning to receive one during the study.******

*****Chronic means more than 14 continuous days.

******Topical, ophthalmic, inhaled, and intraarticular corticosteroids are
acceptable, but receipt of =20 mg/day of prednisone or equivalent for =14
consecutive days in the 4 weeks prior to signing ICF is exclusionary. See exclusion
19 for intranasal steroids.

15. Has received any investigational study product within 60 days, or 5 half-lives,
whichever is longer, before study product administration or is planning to receive
one during the study.

16. Has a history of hypersensitivity or severe allergic reaction******* to any previous
licensed or unlicensed vaccine or the candidate vaccine components (e.g.,
gold).********

*******(e.g., anaphylaxis, generalized urticaria, angioedema, other significant
reaction)

********See IB for vaccine formulation.

17. Received or plans to receive licensed inactivated/subunit vaccine within 14 days of
study product administration or live vaccine within 28 days of study product
administration.

18. Plan to receive a COVID-19 booster vaccine within the 180 days following study
product administration.

19. Regular use of intranasal medications, including steroids.*********

*********Participant must have had no intranasal medication use for 30 days prior to
study product administration and plans not to use intranasal medications for 30 days
after study product administration for medications other than steroids, and for 3
months after study product administration for intranasal steroids (including
over-the-counter [OTC] medications such as Flonase).

20. Use of intranasal illicit drugs in the 5 years prior to study product administration
or plans to use during the study.

21. Current smoker (including cigarettes, marijuana, and vaping) or smoking within the
prior 3 months.

22. History of keloid formation.

23. Current or past scars, tattoos, or other disruptions of skin integrity at the
intended site of study product administration that would preclude adequate
assessment of injection site reactogenicity.

24. History of alcohol or illicit drug abuse within 6 months of enrollment that, in the
opinion of the site PI or appropriate sub-investigator, precludes study
participation.